Ms Barratt said the program has had its critics, but she believes everyone should be entitled to mental health care.

"We don’t seek to condone the crimes that any prisoner has committed. We don’t seek to minimise the gravity of what they have done,” she said.

“But what we do believe is that the prison can be an opportunity for people to get in touch with the best part of themselves."

Ms Barratt believes everyone is entitled to mental health care.

SBS News

Another prisoner, Joe*, told SBS News it is easier to speak openly with a fellow inmate than with an outsider.

"It does help people, because people are afraid to talk to officers because they get branded then as a ‘dobber', or a 'dog' [which] is the main word used for a dobber in jail."

Ms Barratt said those facing language barriers or people from cultural minorities can feel even more isolated in jail.

"It’s difficult enough in prison. But, if you come from a different culture, have a different language, practise a different religion, have different customs, it adds another layer of disconnection."

There were 25 deaths by suicide in South Australian prisons between 1995 and 2010.

Ms Barratt says the Mount Gambier program is definitely working.

"I know it has saved lives. I know from feedback from the listeners themselves. I know from feedback from staff. And I know from my own personal encounters with prisoners, who've said, 'See that man? He saved my life'."

Michelle Price, the general manager of the prison said it also benefits the broader community.

"I think it’s our job, as people who work in custodian environments, to make sure that everybody’s equipped for when they’re released, in order that they don’t perpetrate another crime and have the skillset in order [so] that they can look after themselves as well."

Prisoner peer support programs run in a number of jails across the country. But this one is unique, Ms Price said, because it has been consistently funded since its inception.

South Australia's Minister for Police, Emergency Services and Correctional Services, Corey Wingard, is supportive of the Prisoner Listener program.

"Any death in custody is unacceptable," he said.

For prisoner Shane, “there’s nothing like it”.

“It shows you that everyone can be helped. You just have to put your hand up and say, ‘hey, I need help’.”

*Names have been changed

Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14, Suicide Call Back Service on 1300 659 467 and Kids Helpline on 1800 55 1800 (for young people aged five to 25).